Sicilian Muslims remained citizens of the multi-ethnic County and subsequent Kingdom of Sicily, until those who had not already converted were expelled in the 1240s. Until the late 12th century, and probably as late as the 1220s, Muslims formed the majority of the island's population.[2][3][4][5][6] Their influence remains in some elements of the Sicilian language, as well as surnames and locations.

Around 700, the island of Pantelleria was captured by Arabs, and it was only discord among the Arabs that prevented an attempted invasion of Sicily coming next. Instead, trading agreements were arranged with the Byzantines, and Arab merchants were allowed to trade goods at the Sicilian ports. Attacks from Muslim fleets were repeated in 703, 728, 729, 730, 731, 733 and 734, the last two meeting with a substantial Byzantine resistance.

The first true conquest expedition was launched in 740: in that year the Muslim prince Habib[disambiguation needed], who had participated on the 728 attack, successfully captured Syracuse. Ready to conquer the whole island, they were however forced to return to Tunisia by a Berber revolt. A second attack in 752 aimed only to sack the same city.

In 826 Euphemius, the commander of the Byzantine fleet of Sicily, forced a nun to marry him. Emperor Michael II caught wind of the matter and ordered that General Constantine end the marriage and cut off Euphemius' nose. Euphemius rose up, killed Constantine and then occupied Syracuse; he in turn was defeated and driven out to North Africa.[1] He offered rule of Sicily over to Ziyadat Allah the Aghlabid Emir of Tunisia in return for a place as a general and safety; an Arab army was sent.[1]

The latter agreed to conquer Sicily, promising to give it to Euphemius in exchange for a yearly tribute, and entrusted its conquest to the 70-year-old qadi Asad ibn al-Furat. The Muslim force counted 10,000 infantry, 700 cavalry and 100 ships, reinforced by Euphemius' ships and, after the landing at Mazara del Vallo. A first battle against the loyal Byzantine troops occurred on July 15, 827, near Mazara, resulting in an Aghlabid victory.

Asad subsequently conquered the southern shore of the island and laid siege to Syracuse. After a year of siege, and an attempted mutiny, his troops were however able to defeat a large army sent from Palermo, also backed by a Venetian fleet led by Doge Giustiniano Participazio. But when a plague killed many of the Muslim troops, as well as Asad himself, the Muslims retreated to the castle of Mineo. Later they returned to the offensive, but failed to conquer Castrogiovanni (the modern Enna, where Euphemius died) and retreated back to Mazara.

In 830 they received a strong reinforcement of 30,000 Ifriqiyan and Andalusian troops. The Iberian Muslims defeated the Byzantine commander Teodotus in July–August of that year, but again a plague forced them to return to Mazara and then to Ifriqiya. The Ifriqiyan units sent to besiege Palermo managed to capture it after a year long siege in September 831.[8] Palermo became the Muslim capital of Sicily, renamed al-Madinah ("The City").[9]

The conquest was a see-saw affair; with considerable resistance and many internal struggles, it took over a century for Byzantine Sicily to be conquered. Syracuse held out for a long time but fell in 878, Taormina fell in 902, and the last Byzantine outpost was taken in 965.[1]

In succession Sicily was ruled by the Sunni Aghlabid dynasty in Tunisia and the Shiite Fatimids in Egypt. However, throughout this period, Sunni Muslims formed the majority of the Muslim community in Sicily,[10] with most (if not all) of the people of Palermo being Sunni,[11] leading to their hostility to the Shia Kalbids.[12] The Sunni population of the island was replenished following sectarian rebellions across north Africa from 943-47 against the Fatimids harsh religious policies, leading to several waves of refugees fleeing to Sicily in an attempt to escape Fatimid retaliation.[13] The Byzantines took advantage of temporary discord to occupy the eastern end of the island for several years.

After suppressing a revolt the Fatimid caliph Ismail al-Mansur appointed al-Hasan al-Kalbi (948–964) as Emir of Sicily. He successfully managed to control the continuously revolting Byzantines and founded the Kalbid dynasty. Raids into Southern Italy continued under the Kalbids into the 11th century, and in 982 a German army under Otto II, Holy Roman Emperor was defeated near Crotone in Calabria. With Emir Yusuf al-Kalbi (986–998) a period of steady decline began. Under al-Akhal (1017–1037) the dynastic conflict intensified, with factions within the ruling family allying themselves variously with the Byzantine Empire and the Zirids. After this period, Al-Mu'izz ibn Badis attempted to annex the island for the Zirids, while intervening in the affairs of the feuding Muslims; however, the attempt ultimately failed.[14]

The new Muslim rulers initiated land reforms which in turn, increased productivity and encouraged the growth of smallholdings, a dent to the dominance of the landed estates. The Arabs further improved irrigation systems through qanats, and oranges, lemons, pistachio and sugarcane were introduced to Sicily. A description of Palermo was given by Ibn Hawqal, a Baghdad merchant who visited Sicily in 950. A walled suburb called the Kasr (the palace) is the center of Palermo until today, with the great Friday mosque on the site of the later Roman cathedral. The suburb of Al-Khalisa (Kalsa) contained the Sultan's palace, baths, a mosque, government offices, and a private prison. Ibn Hawqual reckoned 7,000 individual butchers trading in 150 shops. By 1050, Palermo had a population of 350,000, making it one of the largest cities in Europe, second only to Islamic Spain's capital Cordova, which had a population of 450,000. In contrast, under the succeeding Christian Kingdom of Sicily, Palermo's population dropped to 150,000, though it was still the largest city in Europe due to the greater decline in Cordova's population; by 1330 Palermo's population had declined to 51,000.[15]

Arab traveler, geographer, and poet Ibn Jubair visited the area in the end of the 12th century and described Al-Kasr and Al-Khalisa (Kalsa):

The capital is endowed with two gifts, splendor and wealth. It contains all the real and imagined beauty that anyone could wish. Splendor and grace adorn the piazzas and the countryside; the streets and highways are wide, and the eye is dazzled by the beauty of its situation. It is a city full of marvels, with buildings similar to those of Cordoba [sic], built of limestone. A permanent stream of water from four springs runs through the city. There are so many mosques that they are impossible to count. Most of them also serve as schools. The eye is dazzled by all this splendor.

Throughout this reign, continued revolts by Byzantine Sicilians occurred, especially in the east, and part of the lands were even re-occupied before being quashed.[16]

The local population conquered by the Muslims were Romanized Catholic Sicilians in Western Sicily and Greek speaking Christians mainly in the eastern half of the island, but there were also a significant number of Jews.[17] Christians and Jews were tolerated under Muslim rule as dhimmi, but were subject to some restrictions. The dhimmi were also required to pay the jizya, or poll tax, and the kharaj or land tax, but were exempt from the tax that Muslims had to pay (Zakaat). Under Arab rule there were different categories of Jizya payers, but their common denominator was the payment of the Jizya as a mark of subjection to Muslim rule in exchange for protection against foreign and internal aggression. The conquered population could avoid this subservient status simply by converting to Islam. Whether by honest religious conviction or societal compulsion large numbers of native Sicilians converted to Islam. However, even after 100 years of Islamic rule, numerous Greek speaking Christian communities prospered, especially in north-eastern Sicily, as dhimmi. This was largely a result of the Jizya system which allowed co-existence. This co-existence with the conquered population fell apart after the reconquest of Sicily, particularly following the death of King William II of Sicily in 1189.

The Emirate of Sicily began to fragment as intra-dynastic quarrels took place within the Muslim regime.[1] In 1044, under emir Hasan al-Samsam, the island fragmented into four qadits, or small fiefdoms: the qadit of Trapani, Marsala, Mazara and Sciacca; that of Girgenti, Castrogiovanni and Castronuovo; that of Palermo and Catania; and that of Syracuse. By 1065, all of them had been unified by Ayyub ibn Tamim, the son of the Zirid emir of Ifriqiyya. In 1068 he left Sicily, and what remained under Muslim control fell under two qadits: one, led by Ibn Abbad (known as Benavert in western chronicles) in Syracuse, and the other under Hammud in Qas'r Ianni (modern Enna).

By the 11th century mainland southern Italian powers were hiring Norman mercenaries, who were Christian descendants of the Vikings; it was the Normans under Roger I who captured Sicily from the Muslims.[1] The Norman Robert Guiscard, son of Tancred, invaded Sicily in 1060. The island was split between three Arab emirs, and the sizable Christian population rose up against the ruling Muslims.[18] After taking Apulia and Calabria, Roger I occupied Messina with an army of 700 knights. In 1068, Roger de Hauteville and his men defeated the Muslims at Misilmeri. Catania fell in 1071, followed, after one year of siege, by Palermo in 1072. The Normans captured Syracuse in 1086.

The loss of the main port cities dealt a severe blow to Muslim power on the island. The city of Qas'r Ianni was still ruled by its emir, Ibn Al-Hawas, who held out for years. His successor, Hamud, surrendered, and converted to Christianity, only in 1087. After his conversion, Ibn Hamud subsequently became part of the Christian nobility and retired with his family to an estate in Calabria provided by Roger I. In 1091, Butera and Noto in the southern tip of Sicily and the island of Malta, the last Arab strongholds, fell to the Christians with ease. After the conquest of Sicily, the Normans removed the local emir, Yusuf Ibn Abdallah from power, but did so by respecting Arab customs.[19]

The Norman Kingdom of Sicily under Roger II has been characterized as multi-ethnic in nature and religiously tolerant.[20] Normans, Jews, Muslim Arabs, Byzantine Greeks, Lombards and native Sicilians lived in relative harmony.[21][22]Arabic remained a language of government and administration for at least a century into Norman rule, and traces remain in the language of Sicily and evidently more in the language of Malta today.[7] The Muslims also maintained their domination of industry, retailing and production, while Muslim artisans and expert knowledge in government and administration were highly sought after.[23]

However, once the Normans had conquered the island, the Muslims were faced with the choice of voluntary departure or subjection to Christian rule. Many Muslims chose to leave, provided they had the means to do so. “The transformation of Sicily into a Christian island”, remarks Abulafia, “was also, paradoxically, the work of those whose culture was under threat”.[24][25] Despite the presence of an Arab-speaking Christian population, Muslim peasants received baptism from the Roman and Greek Christians and adopted even Greek Christian names; in several instances, Christian serfs with Greek names listed in the Monreale registers had living Muslim parents.[26][27]

However, the Norman rulers followed a policy of steady Latinization. Some Muslims chose the option of feigning conversion, but such a remedy could only provide individual protection and could not sustain a community.[28]

‘Lombard’ pogroms against Muslims started in the 1160s. Muslim and Christian communities in Sicily became increasingly geographically separated. The island’s Muslim communities were mainly isolated beyond an internal frontier which divided the south-western half of the island from the Christian north-east. Sicilian Muslims, a subject population, were dependent on the mercy of their Christian masters and, ultimately, on royal protection. When King William the Good died in 1189, this royal protection was lifted, and the door was opened for widespread attacks against the island’s Muslims. This destroyed any lingering hope of coexistence, however unequal the respective populations might have been. Henry VI’s death in 1197, and that of his wife Constance a year later, plunged Sicily into political turmoil. With the loss of royal protection and with Frederick II still an infant in papal custody, Sicily became a battleground for rival German and papal forces. The island’s Muslim rebels sided with German warlords like Markward von Anweiler. In response, Innocent III declared a crusade against Markward, alleging that he had made an unholy alliance with the Saracens of Sicily. Nevertheless, in 1206 that same pope attempted to convince the Muslim leaders to remain loyal.[29] By this time, the Muslim rebellion was critical, with Muslims in control of Jato, Entella, Platani, Celso, Calatrasi, Corleone (taken in 1208), Guastanella and Cinisi. In other words, the Muslim revolt extended throughout a whole stretch of western Sicily. The rebels were led by Muhammad Ibn Abbād. He called himself the ‘prince of believers’, struck his own coins, and attempted to find Muslim support from other parts of the Muslim world.[30][31]

However, Frederick II, no longer a child, responded by launching a series of campaigns against the Muslim rebels in 1221. The Hohenstaufen forces rooted out the defenders of Jato, Entella, and the other fortresses. Rather than exterminate the Muslims, in 1223, Frederick II and the Christians began the first deportations of Muslims to Lucera in Apulia.[32] A year later, expeditions were sent against Malta and Djerba, to establish royal control and prevent their Muslim populations from helping the rebels.[30] Paradoxically, Saracen archers were a common component of these “Christian” armies from this era.[33]

The House of Hohenstaufen and their successors (Capetian House of Anjou and AragoneseHouse of Barcelona) gradually "Latinized" Sicily over the course of two centuries, and this social process laid the groundwork for the introduction of Latin (as opposed to Byzantine) Catholicism. The process of Latinization was fostered largely by the Roman Church and its liturgy. The annihilation of Islam in Sicily was completed by the late 1240s, when the final deportations to Lucera took place.[34]